I had this idea long ago, before
Voice of All was printed. It originally cost 2W and didn't have first strike. The casting cost was changed and first strike was added to make it more like Voice of All, but it was still unremarkable. With the recent keywording of "Attacking doesn't cause ~this~ to tap", I thought it would be more flavorful (and more powerful) to give Righteous Crusader Vigilance rather than first strike:
Righteous Crusader
1WW
Creature -- Knight
2/2
Vigilance
(Attacking doesn't cause this creature to tap.)As Righteous Crusader comes into play, choose a color.
Righteous Crusader has protection from the chosen color.